First HPDE: Sonoma Raceway

[csamsh]

Something else is going to be needed.

Want to get better at placing the car where you want it?

Autocross....

 

[kcbrown]

I didn't think the suspension was all that soft before hitting the track, either (well, there are a couple of spots on the commute home that hint at it). Once I got it out running at speed I could feel just how much suspension movement there was. No, not a showstopper, but having had a lowered car, I know there is a ton of improvement available in that one place alone.

I have to wonder if the perception of suspension movement is largely dictated by smoothness.

Which is to say, I have to wonder if, when you drive the car really smoothly, the movement of the suspension winds up being much less noticeable than if you drive it with abrupt transitions.

I drive my car smoothly perhaps to a fault, with everything being done as gradually as possible, including left to right transitions. Enough so that I actually want to slightly modify my line at Sonoma Raceway to make a couple of the transitions smoother!

Now that I've got a year of autocrossing and a track day under my belt, I'm comfortable with starting to throw parts at it. I'm a set of camber plates shy of getting it lowered. Hopefully in about a month, that will be done. Then to see what effects it had--and play with/learn tuning with the adjustable shocks.

Ah. I'd forgotten that it was autocrossing that you've been doing. Have you taken the car onto a race track yet?

I've done autocrossing before, but it was a long time ago. I know from that experience that autocross transitions are much more abrupt than track driving transitions, because everything happens so quickly and in such tight confines that you really don't have much of a choice. I expect the Mustang in stock trim isn't going to be terribly good at autocross (but would bet money that the stock 2011+ S197 GTs with the Brembo Brakes are miles ahead of the Fox bodies as regards suspension behavior).

On the road course, the stock GT Track Package is really good. I may be speaking from lack of experience here, but I have ridden in other cars with much tighter suspensions, and those cars simply didn't feel substantially more precise than my car does. I was really impressed with the kind of precision I was able to get out of my car, and that's with just being a novice at this.


On stickier tires (e.g., slicks), it may be that the stock suspension won't cut it. But aside from some apparent body lean (something I'll need to verify the next time I take the car onto the track, since it may be that what was leaning was me!), I actually have no real complaints so far.

I fully expect that whatever excess suspension motion I'm getting right now will be eliminated with springs with twice the rate of what I've got right now, including excess brake dive.

 

[kcbrown]

Want to get better at placing the car where you want it?

Autocross....

I don't have a problem placing the car where I want when I'm watching what I'm doing. When I'm doing that, I can place the car where I want it with great precision.

The problem is that if I'm doing that, then I can't pay attention to anything else.

At least, not yet. I'm hopeful that getting used to the experience will help in that regard, that I'll be able to "time slice" between watching my line on the track and watching other things.

 

[claudermilk]

I have to wonder if the perception of suspension movement is largely dictated by smoothness.

Which is to say, I have to wonder if, when you drive the car really smoothly, the movement of the suspension winds up being much less noticeable than if you drive it with abrupt transitions.

I drive my car smoothly perhaps to a fault, with everything being done as gradually as possible, including left to right transitions. Enough so that I actually want to slightly modify my line at Sonoma Raceway to make a couple of the transitions smoother!

Smoothness isn't an issue. In fact, just about every time I've had an instruthor in the car, this is something they comment on--my inputs are very smooth. The instructor for the track day mainly just showed me the line for the first couple of laps, then kept telling me to get on the power earlier, hit my apexes better, and let the car track out more--basically fine-tuning the basics.

Ah. I'd forgotten that it was autocrossing that you've been doing. Have you taken the car onto a race track yet?

Yep, once thus far. Completely different world and that experience displayed the suspension's characteristics in a different way. Things happened a bit more slowy, so I actually had time to analyze what the car was doing.

I've done autocrossing before, but it was a long time ago. I know from that experience that autocross transitions are much more abrupt than track driving transitions, because everything happens so quickly and in such tight confines that you really don't have much of a choice. I expect the Mustang in stock trim isn't going to be terribly good at autocross (but would bet money that the stock 2011+ S197 GTs with the Brembo Brakes are miles ahead of the Fox bodies as regards suspension behavior).

Yes, autocross transitions can be quite violent and everything happens really quickly. It's all tight, quick transitions. With that, the stock S197 suspension wallows all over the place; it's just happening very quickly and I am concentrating so much on my line & next move that it isn't so apparent to me--aside from loss of traction at either end (depending on how I screwed up that particular corner). I've found autocross in an S197 is largely composed of rear traction management. This is a good thing for me, since I really needed to learn that.

On the road course, the stock GT Track Package is really good. I may be speaking from lack of experience here, but I have ridden in other cars with much tighter suspensions, and those cars simply didn't feel substantially more precise than my car does. I was really impressed with the kind of precision I was able to get out of my car, and that's with just being a novice at this.

I won't argue that. The car performed amazingly well and that was not a big surprise to me--this characteristic is what attracted me to the S197 platform. I was able to place it about where I meant to, and it held the corners really well. The Mustang in simply much happier on an open track vs a tight autocross course. That said, as I mentioned with input requirements slowing down a lot, I was able to spend some brain power analyzing what the suspension was doing. Part of that was running at nearly 130 on a superspeedway front straight--lots of time to think about suspension movement. There was a lot of it. Watching some external video a friend shot of the car verified what I was feeling. He also shot a recent autocross & I saw the same thing--lots of lean, and worse, massive brake dive.

Having gone from a stock suspension to basic lowering springs/struts on a previous car ('95 Probe GT on Tokico Illuminas & Eibach Pro Kits), I am familiar with the difference. Done right it helps a lot. I am in the process of gathering parts for the Mustang to do that now--going to Koni yellows & Steeda Sports with Vorshlag CC plates. That should help with the moving around & give me some tuning ability to play with (but not too much to get confused).

I'm sure we've all read through Terry's thread with his detailed write-ups of what he's been learning going from stock to his uber-dollar setup. One of the basic things I get from all that is buttoning the chassis down with higher spring rates & better dampers improves the car immensely. But now I'm getting off your main topic of the driver mod.

 

[Norm Peterson]

I think you need to learn to trust what you are feeling back through the steering wheel and seat, and what you're hearing from the tires (at least). If the situation starts heading south, I think you'll pick up those messages before the car has aimed itself far enough off line for you to see that you're going off line, and it'll help you keep your head/eyes up more of the time. I hope I'm explaining this the way I think I am. 50 years driving has a way of putting conscious thought of what I'm doing under any given situation off in the background.

This past weekend I was at a Friday-Saturday Hooked On Driving event at NJMP, and the second day it rained the whole time. It's pretty easy to feel when the tires start to be less than completely stuck down, and it's a whole lot of fun when you can get about the same amount of sliding in the same slow corner lap after lap. Potentially a huge confidence-builder.

The frantic pace of autocross is good training - there are relatively few places on the big tracks where you'll need to be steering from a right turn directly into a left turn with no hint of a straight in between, so in that respect the track is a bit more relaxing. Further, you have to keep looking up, and you should eventually learn to ignore chassis roll and pitch. Truthfully, I hardly notice roll at all any more and nose dive under braking only during hard stops when I'm specifically paying attention to that. The way I figure it, it's what the car is going to do no matter what I think, and worrying about it isn't going to make it go away.


One thing I didn't mention earlier about track driving vs ramp driving - on the street there aren't any flag stations, so it's an easier mental load on the street that you have to consciously take another step with at the track.


Incidentally, the '95 Mazda 626 that I still have has been modified in much the same way as your PGT . . . plus at least one other thing I doubt many people try.


Norm

 

[kcbrown]

I think you need to learn to trust what you are feeling back through the steering wheel and seat, and what you're hearing from the tires (at least). If the situation starts heading south, I think you'll pick up those messages before the car has aimed itself far enough off line for you to see that you're going off line, and it'll help you keep your head/eyes up more of the time. I hope I'm explaining this the way I think I am. 50 years driving has a way of putting conscious thought of what I'm doing under any given situation off in the background.

Well, I was hoping to use peripheral vision as a way of allowing me to look around at my environment while simultaneously seeing that I'm driving the line properly. This latest experimental failure has shown me that I can't do that, at least with respect to using peripheral vision as the primary reference for that.

I would expect that I'd feel the car shifting out of place relative to where I want it to be in the event things start going south, but this experiment wasn't for that, it was for maintaining awareness of where I want the car to be to begin with. And for that, it seems I have to actually look at where I want the car to go.

It is what it is. If I can't do that through peripheral vision (as the experiment indicates), then I must do it through primary vision. There's nothing else left.

I'm thus hoping that my peripheral vision will work for a general awareness of traffic around me, but it certainly won't work with respect to corner workers. Otherwise, I wouldn't have had trouble seeing them to begin with. Time will tell if that changes. There's a bit of sensory overload when starting out, and I surely experienced some of that.


One other potentially relevant item: I'm treating this as if there is no margin for error, because errors can get you or someone else injured or killed on the track. As such, there is no way I'm going to put my trust in something that isn't well-proven, most especially as regards my own abilities.

The frantic pace of autocross is good training - there are relatively few places on the big tracks where you'll need to be steering from a right turn directly into a left turn with no hint of a straight in between, so in that respect the track is a bit more relaxing. Further, you have to keep looking up, and you should eventually learn to ignore chassis roll and pitch. Truthfully, I hardly notice roll at all any more and nose dive under braking only during hard stops when I'm specifically paying attention to that. The way I figure it, it's what the car is going to do no matter what I think, and worrying about it isn't going to make it go away.

I've been thinking about autocross. My experience with it wasn't terribly good. 60 seconds worth of intense driving followed by a couple of hours of waiting followed by another 60 seconds of intense driving isn't a good way for me to learn anything, because there just isn't enough repetition.

Now, if I had exclusive access to the autocross course for a while, that would be a different story, but autocross events are not, to my knowledge, operated that way. There's just too much demand for them for that.

Oddly enough, I didn't really notice the roll of the car too terribly much while driving on the track. I was focused too intensely on what I was doing for that. I only noticed it enough to have a small amount of awareness that it's what the car was doing. And again, it may be as much me leaning in the car as the car itself leaning that I was noticing. I expect that as I learn the line more thoroughly, my awareness of other things, like how the car is behaving, will increase. I'm hoping that my awareness of the corner workers and the traffic increases as a side effect.

One thing I didn't mention earlier about track driving vs ramp driving - on the street there aren't any flag stations, so it's an easier mental load on the street that you have to consciously take another step with at the track.

Right. And that's the hurdle I'm trying to overcome.

 

[kcbrown]

By the way, I'm not going to entirely give up on the idea of using my peripheral vision for car control. I'm going to continue to practice it in situations where there's not even a chance of damaging the car in the process. That may limit the kinds of corners I can take in the process, but it may be that merely practicing it will confer some ability to use it in tighter corners on the track. For tighter corners, the only place I'll be able to try it out is on the track, and then only for corners where it's not a problem if I go off on one side entirely (e.g., as a result of clipping the apex or going off at track out).

I expect the track work for that will wind up taking a back seat to other things, so it may be a while before peripheral vision becomes really useful here, but I'm not going to entirely discard its use out of hand before I've given it a fair shake.

Even so, let's assume for the moment that peripheral vision is out of the picture for primary car control. What other options are on the table for managing the car and maintaining awareness of the corner workers and the traffic? Anything else that hasn't been covered yet?

 

[Norm Peterson]

By the way, I'm not going to entirely give up on the idea of using my peripheral vision for car control. I'm going to continue to practice it in situations where there's not even a chance of damaging the car in the process. That may limit the kinds of corners I can take in the process, but it may be that merely practicing it will confer some ability to use it in tighter corners on the track. For tighter corners, the only place I'll be able to try it out is on the track, and then only for corners where it's not a problem if I go off on one side entirely (e.g., as a result of clipping the apex or going off at track out).

I expect the track work for that will wind up taking a back seat to other things, so it may be a while before peripheral vision becomes really useful here, but I'm not going to entirely discard its use out of hand before I've given it a fair shake.

Don't forget what Dave posted earlier. Boldface mine.

Approaching braking zone, quick mirror check, corner station check, then focus on your braking point, and the instant you commit (start to pull your foot off the gas), shift your eyes up to your turn-in point.
At the point where you start to turn the wheel in, lift your eyes up and over to your track-out point. Use peripheral vision to track A) progress towards apex (may have to flick vision there to confirm)*, and B) scan through exit for traffic, debris, flags, etc.

* Now the way that I teach cornering is based on the "single input" concept, so it really only takes a quick flick of the eyes perhaps midway between turn-in and apex to confirm your arc if you're not getting the right peripheral cues (Hmm, this doesn't feel right). Maybe 100mS total. Don't study it. "Am I close?" If yes, great, eyes back to exit. If not, then and only then, keep your attention on apex and correct. Usually if you're not on, it's going to take a wheel motion to correct and your corner is blown. Use the eye-flick verification if the corner just doesn't "feel" right.

At 6/10ths or 7/10ths you have some extra margin to cover for a bit of sloppiness (early apex, too wide, a little too hot). Unless you momentarily get way in over your head you'll still have enough grip left to be able to make steering corrections if that's what it takes to stay on the black stuff.

As for autocross, sometimes you can find a Regional test & tune day where you will get repeated opportunities to negotiate a variety of course elements. For a little more investment, Evolution school will provide top-shelf instruction by people who are or who have been National champions or contenders. Either of these involves a limited number of students, which will maximize your seat time.


Norm

 

[claudermilk]

The frantic pace of autocross is good training - there are relatively few places on the big tracks where you'll need to be steering from a right turn directly into a left turn with no hint of a straight in between, so in that respect the track is a bit more relaxing. Further, you have to keep looking up, and you should eventually learn to ignore chassis roll and pitch. Truthfully, I hardly notice roll at all any more and nose dive under braking only during hard stops when I'm specifically paying attention to that. The way I figure it, it's what the car is going to do no matter what I think, and worrying about it isn't going to make it go away.

This. I couldn't have said it better myself. THough only having a single track day under my belt & thus nowhere near an expert, this is exactly the differences I noted. In an autocross you get a lot of compressed practice in extreme transitions. I think it was excellent prep for the track. The couple of time I did actually get one end or the other a little loose, it seemed like there was plenty of time to analyze & react to it as compared to autocross. For my part, it isn't so much worrying about the movement as much as noting that it is a place for improvement.

Incidentally, the '95 Mazda 626 that I still have has been modified in much the same way as your PGT . . . plus at least one other thing I doubt many people try.

Norm

OT sidebar... Cool, as we know the 626/MX-6/Probe were the same platform. I also had a RRE custom front strut brace, rear strut brace & a custom rear sway (17.5mm from a Probetalk group buy). The car was amazingly well balanced wth that. The only two things I wanted to do beyond that was an MX-6 front swaybar & camber plates. After that it would have been a full coilover swap. I was sad when I had to sell that car.


Back on topic, kc, are there practice events, novice school, or possibly an Evolution school event available in your area? You will get a lot more repetition that way. I was able to take the Phase 1 program, and it was well worth it. Lots of track time, instructor time, and a ton was learned. (lol, I see Norm mentions the same thing--Evolution school really is that good).

Also, good to hear you will continue with your peripheral experiment. I am thinking perhaps more time to get used to the idea may be needed. As always: practice & seat time.

 

[kcbrown]

I wouldn't know where to look for practice events, novice schools, etc. (that are any good, at any rate), but there is an Evolution phase 1 and phase 2 event in Marina, CA on 7/19 and 7/20. I guess I should sign up for it!

Assuming I've got nothing conflicting with that, it'll be good, because I'll have done my second NASA track event (again at Sonoma Raceway) a month prior.

 

[Norm Peterson]

The value of seat time alone should make it worthwhile. I would expect your local SCCA region and other clubs such as PCA or BMWCCA to have test & tune sessions and novice driver autocross schools posted in their schedules.


Norm

 

[claudermilk]

Absolutely sign up for it if you can!

There is tons of seat time, much of it with an instructor. The instructors also have you ride while they drive your car so you can see what it is actually capable of.

The basic format on phase 1 is they talk you through the section being covered, then you drive the section with the type of feature laid out. You cycle through several of these and at the end of the day, you do a full 3-run autocross on the whole course. After every time you drive a section or run, the instructor gives feedback before you go out again.

 

[dontlifttoshift]

Evo school will make you a better driver. period. It really is a deal at twice the price.

 

[kcbrown]

Guess I didn't mention it here, but I have in fact signed up for the Evolution school in Marina. It's something I'm very much looking forward to, as is the HPDE in mid-June at Sonoma.

So far, I'm signed up for those, the NASA event at Thunderhill in August, and the NASA event at Sonoma in September. I'm looking around for additional events in October, November, and December, and haven't been finding any (NASA has something, but it's HPDE4 only). Anyone know of any in the Northern California region for October, November, and December? Or is it simply too early to sign up for those?

 

[NoTicket]

NCRC has several events at Thunderhill, Laguna, and Buttonwillow all through Aug-Oct.

 

[kcbrown]

350lb rear springs sounds like a lot. Any reason why you're ditching the "conventional" wisdom and going for a bigger rear than front? More spring in the front would help with your roll/camber/tire wear problems too.

I can now give you a better answer to this question.

I might not wind up using quite that much spring in the rear. It depends on what the calculations work out to be.

However, the reason my spring rates are going to look different from that of everyone else is that everyone else is lowering their car by an inch or more, while I'm not. Lowering the front of the car drops the roll center by more than the car is lowered, by a 3:1 ratio, so the end result is that the roll moment arm is actually increased.

Conversely, when you lower the rear, the roll center drops by less than the amount you're lowering the car (as it's the height of the Panhard bar at the center, if I'm not mistaken, and thus drops roughly by a 1:2 ratio), and thus the roll moment arm is reduced. The ratio of those two arms changes by the square of the amount you lower the car.


That results in greater roll for a given spring rate in the front, and less roll for a given spring rate in the rear, relative to what you'd get if you used those same springs at stock ride height, which means that the overall weight transfer in roll moves rearward, and thus induces greater oversteer. So in order to maintain the same balance when lowering your car, you have to use stiffer springs up front relative to the rear. And because that ratio of arm lengths changes with the square of the amount you lower the car, lowering the car a bit will require a substantial spring rate balance change just to maintain the balance of the car.


So why will my spring rates be so much different than conventional wisdom might have it? Because I'm not lowering the car much at all for a number of reasons (some practical, some for the purpose of maintaining suspension geometry). Indeed, there's a good chance I'll keep the ride height at stock values and simply increase the spring rates. I won't need as much spring rate up front to control roll as you guys do because the roll moment arm will be that much less. Pitch due to braking will be reduced due to the larger amount of spring on both ends, but I may also use relocation brackets in the rear to change the geometry to help with that. I'll be making one change at a time, however.

 

[Norm Peterson]

Pitch due to braking will be reduced due to the larger amount of spring on both ends, but I may also use relocation brackets in the rear to change the geometry to help with that. I'll be making one change at a time, however.

Be a little careful here and don't be in any hurry to tweak this. Revising the LCA inclination for greater anti-squat also changes the axle steer, and in this case it will result in "looser" behavior (which I think that you in particular might find disconcerting at times when you're already kind of busy).


Norm

 

[ArizonaGT]

I agree with Norm on the brackets. Lowering the LCAs works well for traction on low-speed tracks, but at high speed tracks like Sonoma they will just make the car loose in roll at high speeds--you don't want that.